Applicant filed Ser. No. 853,341 on Apr. 17, 1986, which issued as U.S. Pat. No. 4,705,540 on Nov. 10, 1987; Ser. No. 923,485 on Oct. 27, 1986, which issued as U.S. Pat. No. 4,717,393 on Jan. 5, 1988; and, Ser. No. 923,486 on Oct. 27, 1986, which issued as U.S. Pat. No. 4,717,394 on Jan. 5, 1988. These references concern polyimide membranes.
U.S. Pat. No. 4,629,685 and U.S. Pat. No. 4,629,777 disclose alkyl substituted aromatic polyimides for use in the electronics industry.
U.S. Pat. No. 3,822,202 and U.S. Re No. 30,351 disclose aromatic polyimide gas separation membranes in which the molecular structure is such that the molecules in the polymer are unable to pack densely and, therefore, have high gas permeation rates.
U.S. Pat. No. 4,378,400 discloses aromatic polyimide gas separation membranes in which the molecular structure is such that the molecules in the polymer can pack densely.